Comparative assessment of the recognition of domain-specific CD163 monoclonal antibodies in human monocytes explains wide discrepancy in reported levels of cellular surface CD163 expression

Epitope accessibility and extracellular calcium dependence elucidate discrepancies in reported levels of monocytic CD163 expression. Utilizing monoclonal antibodies to the N-terminal part of CD163 more than 80% monocytes in human peripheral blood could be identified as CD163 positive, indicating that most, and conceivably all, human peripheral blood monocytes do express CD163.